<!--$Id: db_fd.so,v 10.31 2005/06/14 14:06:57 bostic Exp $-->
<!--Copyright (c) 1997,2008 Oracle.  All rights reserved.-->
<!--See the file LICENSE for redistribution information.-->
<html>
<head>
<title>Berkeley DB: Db::fd</title>
<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++">
</head>
<body bgcolor=white>
<table width="100%"><tr valign=top>
<td>
<b>Db::fd</b>
</td>
<td align=right>
<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a>
<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td>
</tr></table>
<hr size=1 noshade>
<tt>
<b><pre>
#include &lt;db_cxx.h&gt;
<p>
int
Db::fd(int *fdp);
</pre></b>
<hr size=1 noshade>
<b>Description: Db::fd</b>
<p>The Db::fd method provides access to a file descriptor representative
of the underlying database.  A file descriptor referring to the same
file will be returned to all processes that call <a href="../api_cxx/db_open.html">Db::open</a> with
the same <b>file</b> parameter.</p>
<p>This file descriptor may be safely used as a parameter to the
<b>fcntl</b>(2) and <b>flock</b>(2) locking functions.</p>
<p>The Db::fd method only supports a coarse-grained form of locking.
Applications should instead use the Berkeley DB lock manager where possible.</p>
<p>The Db::fd method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</p>
<b>Parameters</b> <br>
 <b>fdp</b><ul compact><li>The <b>fdp</b> parameter references memory into which
 the current file descriptor is copied.</ul> 
<br>
<hr size=1 noshade>
<br><b>Class</b>
<a href="../api_cxx/db_class.html">Db</a>
<br><b>See Also</b>
<a href="../api_cxx/db_list.html">Databases and Related Methods</a>
</tt>
<table width="100%"><tr><td><br></td><td align=right>
<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a>
</td></tr></table>
<p><font size=1>Copyright (c) 1996,2008 Oracle.  All rights reserved.</font>
</body>
</html>
